() \(\sigma_{12}=\frac{2k\sigma_{T}}{x_{2}-x_{1}}\sqrt{\frac{1}{\delta_{2}^{2}}+\frac{1}{\delta_{1}^{2}}}\ \ ,\ \text{and}\ \)
() \(\sigma_{23}=\frac{2k\sigma_{T}}{x_{3}-x_{2}}\sqrt{\frac{1}{\delta_{3}^{2}}+\frac{1}{\delta_{2}^{2}}}\text{\ \ .\ \ \ \ \ \ \ \ }\)